Pass-line displacement roll for cooling strip in cold-rolling mill



Sept. 15, 1970 w. L. ROBERTS 3,523,268 PASS-LINE DISPLACEMENT ROLL FOB. COOLING STRIP IN COLD-ROLLING MILL Filed Feb. 12, 1968 2 Sheets-Sheet 1 1 Low Pressure l l i l I High Pressure i l l i l LL14 30 "1 INVENTOR.

High Pressure WILLIAM L. ROBER T8 A! farney T0 COILER Sept. 15, 1970 PASS-LINE DISPLAdEMENT ROLL FOR COOLING STRIP Filed Feb. 12, 1968 w ROBERTS 3,528,268

IN COLD-ROLLING MILL 2 Sheets-Sheet :3

36 44 g l 48 I 46 I/ S f D. 6. Low Pressure Amp/Hie,-

High Pressure D. 0. Amplifier INVENTORp WILLIAM L. ROBERTS A! rorney United States Patent 3,528,268 PASS-LINE DISPLACEMENT ROLL FOR COOLING STRIP IN COLD-ROLLING MILL William L. Roberts, Murrysville, Pa., assignor to United States Steel Corporation, a corporation of Delaware Filed Feb. 12, 1968, Ser. No. 704,820 Int. Cl. B21b 37/10 US. C]. 72-13 1 Claim ABSTRACT OF THE DISCLOSURE Roll of invention cooperates with two fixed rolls to loop a continuous metal strip being cold rolled in a tandem rolling mill. Such looping extends the length of the strip pass-line and lowers the temperature of the strip. Fluid spray means may be provided adjacent the loop path of the strip to effect further lowering of the strip temperature. Also disclosed is a temperature-sensing element and electrical control means whereby the roll of the invention is actuated automatically in response to strip temperature.

The present invention relates generally to the processing of metal strip and more particularly to an improved and unique pass-line displacement roll arrangement especially suitable for cooling stn'p being cold rolled in a tandem rolling mill.

As is well known, in the rolling of steel strip in highspeed, tandem cold-rolling mills, it is important that the coiling temperature of the strip be maintained below approximately 450 F., so that the metallurgical properties of the strip, particularly when processed into tinplate, are not adversely affected. This consideration, in effect, limits the speed of multi-stand cold-rolling mills, which are sufliciently powered to process strip at speeds greater than now prevail.

Initially, it may be thought possible to maintain the coiling temperature of cold-rolled strip below desired levels simply by increasing the amount of coolant applied to the strip as it is being rolled. However, this procedure is not feasible with presently used lubricantcoolants. It is currently usual practice to use palm oils or suitable equivalents as lubricant-coolants during cold rolling. These lubricants are almost solids at room temperature and, therefore, in use must be maintained at temperatures in excess of approximately 130 F., to ensure that they retain liquid form. Another factor which limits the cooling efliciency of present-day lubricant oils is that the lubricity of the oil improves with increasing temperature. In this regard, it should also be noted that the rate at which the lubricant oil plates out on the strip increases with increasing temperatures. Therefore, until improved rolling lubricants are developed that will operate efiiciently at lower solution temperatures, it is not feasible to attempt to lower rolling or coiling temperatures by reducing the temperature of the coolant and/ or increasing its rate of flow to the mill.

The present invention contemplates achieving lower coiling temperatures by increasing the area of strip exposed to the lubricant as the strip is being processed in the cold-rolling mill. 7

It is, accordingly, the primary object of my invention to provide a displacement roll arrangement adjacent the strip-pass line of a rolling mill whereby the strip may be looped selectively to expose greater areas thereof to a lubricant-coolant.

It is a more specialized object of my invention to provide a roll arrangement of the character set forth above wherein a pair of rollers are disposed in a fixed plane on one side of a strip-pass line extending transversely thereof, and another roll is normally disposed on the other side 3,528,268 Patented Sept. 15,, 1970 FIG. 2 is an enlarged elevational view of the passline displacement roll arrangement of the invention showing the cooperating roll in elevated position;

FIG. 3 is a perspective of the cooperating ro'll, support yoke and fluid pressure cylinder of the invention; and

FIG. 4 is a diagrammatic illustration of a control means for the invention.

Referring more particularly to the drawing, reference numeral 2 designates generally a two-stand tandem coldrolling mill. Each of the two stands of mill 2 includes a housing 4 in which are journaled a pair of cold working rolls 6 for reducing and applying tension to a strip S, and a pair of back-up rolls 8. Rolls 6 and 8 are mounted and driven in conventional manner. Bridle rolls 10 and 12 are provided spaced from the exit end 14 of mill 2 for maintaining strip S under tension as it passes to a coiler (not shown).

The structure thus far described is conventional and is not claimed as my invention.

The pass-line displacement roll arrangement of the invention is designated generally by reference numeral 16 and is shown installed one between the two housings 4 and one between the exit end of mill 2 and bridle rolls '10 and 12. Each of the roll arrangements 16 shown is identical and includes a pair of rolls 18 rotatably mounted in a fixed plane on one side of the pass-line of mill 2 extending transversely thereof, and a cooperating roll 20 normally disposed on the other side of the passline of mill 2 opposite rolls 18 journaled in bearings 21 in a yoke 22. Yoke 22 is mounted on the projecting end of the piston rod 24 of a fluid pressure cylinder 26 which, in turn, may be mounted by its head end in upright position on the base of a housing 4. The cylinder 26 functions to move yoke 22 and roll 20 between the pair of rolls 18 in a path generally normal to the plane common to the strip-contacting surfaces of the rolls 18. Cylinder 26 is provided with suitable valved connections 28 and 30 "with exhaust lines and fluid pressure lines, as best shown in FIG. 2. Valves 28 and 30, which may be suitably coupled together mechanically, control the operation of cylinder 26.

An inverted substantially U-shaped manifold 32 may be provided above each of the displacement roll arrange ments 16 adapted to receive and enclose the cooperating roll 20 at the upper end of its path of travel, as best shown in FIG. 1. The manifolds 32 are connected with sources of lubricant-coolant under pressure (not shown). A plurality of spray heads 34 is disposed in spaced relation along the inner surface of each of the manifolds 32 for spraying lubricant-coolant on the loop of strip S formed, as shown by broken lines in FIG. 1, when the cooperating roll is raised to extend the pass-line of mill 2. Suitable valves (not shown) may be connected with each of the manifolds 32 to manually or automatically actuate the spray heads 34.

The displacement roll arrangement of the invention may be operated manually by manipulation of the valves 28 and 30 as described above. Alternately, if it is desired to coil the strip at a certain temperature, a feedbackcontrol type system may be used so that the position of the cooperating roll 20 in each arrangement 16 may be automatically adjusted to maintain a preset coiling tem- 3 perature. An example of such a system is shown in FIG. 4 and will now be described.

The temperature of the strip S is measured by means of a specially-constructed roll 36 substituted for the bridle roll shown in FIG. 1. In roll 36 is embedded a temperature-sensing element in the form of a thermocouple 38 having leads 40 and 42 connected internally in roll 36 to slip rings 44 and 46 at the end of the roll. The electrical signal developed by the thermocouple 38 is transferred via slip rings 44 and 46 to brushes 48 and 50, respectively, and is fed to a D-C amplifier 52. The output of amplifier 52 appears across leads 54 and 56. A D-C voltage of opposite polarity is established between an adjustable slider 58 and a lead 60 associated with a potentiometer 62 and a battery 64. The potentiometer 62 constitutes a set-coiling temperature control, the desired coiling temperature being set by suitable adjustment of the slider 58. The difference signal appears on leads 54 and 60 which feed to a D-C amplifier 66. This signal has a polarity corresponding to the direction of the difference and a magnitude corresponding to the magnitude of the diflference. The output signal of D-C amplifier 66 appears on terminals 68 and 70 to which are connected in parallel two circuits 72 and 74, the former consisting of a relay 76, a rectifier 78, and a variable source of potential designated by reference numeral 80. Circuit 74 consists of a relay 82, a rectifier 84, and a variable source of potential 86. The operation of these circuits is as follows: if the signal between leads 54 and 60 does not exceed a certain value, or values (determined by the settings of the variable sources of potential 80 and 86), relays 76 and 82 are not energized. If the input signal to amplifier 66 exceeds a certain positive value, relay 76 will be energized; if the input signal exceeds a certain negative value, relay 82 will be energized.

Energization of relay 76 also energizes a pair of solenoid valves 88 and 90 connected in series with a battery 92 and contacts 94 of relay 76. This causes fluid to be pumped into the head end of fluid pressure cylinder 26 causing the piston rod 24 to project and lift yoke 22 and cooperating roll 20 to raised position, as shown by broken lines in FIG. 1. Energization of relay 82 causes energization of a pair of solenoid valves 96 and 98 which are wired in series with a battery 100 and the contacts 102 of relay 82. Energization of solenoid valves 96 and 98 causes the piston rod 24 to be retracted and the roll 20 and yoke 22 to move downward to the position shown by solid lines in FIG. 1.

The polarities of the signals associated with amplifiers 52 and 66 are such that:

(1) If the coiling temperature of strip S as measured by the thermocouple 38 in roll 36 corresponds closely with that preset on potentiometer 62, the contacts of relays 76 and 82 remain open and cooperating roll 20 is not moved;

(2) If the coiling temperature is too high, relay 76 is energized causing its contacts 94 to close completing a circuit to and actuating solenoid valves 88 and which causes the roll 20 to move upward extending the pass line of the mill so that a greater area of the strip S is exposed to the lubricant-coolant; and

(3) If the coiling temperature is too low, relay 82 is energizedcausing its contacts-102 to close and a circuit to be completed to solenoid valves 96 and 98 so that the roll 20 is lowered so that the pass-line of the mill returns to its normal length.

While I have shown but one embodiment of my invention, it, will be apparent that other adaptations and modifications may be made without departing from the scope of the following claim.

I claim:

1. In a continuous strip processing line having a pass line with an entry end and an exit end, and strip tensionapplying means adjacent said entry end and said exit end the improvement therewith which comprises a pair of spaced elongated rollers extending transversely of said processing line mounted for rotation in a fixed plane on one side of said pass line and disposed between said strip tension-applying means, said rollers having a surface adapted to contact strip being processed in said line, a cooperating roller normally disposed on the other side of said pass line, means rotatably supporting said cooperating roller, said cooperating roller and support means being movable between said pair of elongated rollers in a path generally normal to the plane common to the strip contacting surfaces of said last-mentioned rollers, means for moving said cooperating roller and supporting means in said path, said means for supporting said cooperating roller including a yoke in which said cooperating roller is supported journaled in anti-friction bearings, said means for moving said cooperating roller and supporting means in said path including a fluid pressure cylinder, said yoke being connected with the piston rod of said cylinder, at temperature-sensing element mounted adjacent said pass line at the exit end of said strip processing line, means connected with said temperature-sensing element for receiving an electrical signal from said element, and electrically actuated control means connected with said cylin der, said last-named control means being in circuit with said signal-receiving means and adapted to be actuated by said signal to operate said cylinder to move said cooperating roller and supporting means in said path.

References Cited UNITED STATES PATENTS 2,226,500 12/1940 Matthews 7213 X 3,289,449 12/1966 OBrien 72-20l MILTON S. MEHR, Primary Examiner U.S. Cl. X.R. 

